Gay, in the english language, is usually used to refer to males, though females can also use it.
As for yuri, it is a type of manga genre in japan which involves lesbians. If I remember, they use adaptations of the english word "Lesbian" for lesbians. I think they also have some punny, food related slang for it, too, but that might be for gay men.
As for the image, strictly speaking, this does not apply. Though it is generally accepted by internet folk to mean "lesbian", and almost always applied to illustrations and animated features or what have you. Why do I mention this? Useless trivia and specifics are fun, that's why.